As CPU computing power improves continuously over the last decades, electronic devices are getting ever more powerful and smaller in size. Handheld or mobile devices are becoming more and more popular, and can perform more and more functions. There have emerged pagers, mobile or cellular phones, PDAs (personal digital assistants), MP3 players, digital cameras, smart phones, tablet computers, and etc. Typically, a handheld electronic device has a digital display to show text, image or video, and a speaker to play music or voice. It also has buttons or a keyboard either physically or on the display as a touchable screen to interface with a user, and realizes functions such as transferring voice or text message, playing music or video, taking pictures or recording video, accessing email or doing web browsing. Handheld electronic devices have dramatically changed people's lifestyle in the last couple of decades.
Because of their mobile nature, handheld electronic devices are subject to mechanical damages due to dropping, hitting, or scratching, and environmental conditions, such as exposing to water or moisture, and collecting dust, dirt, grease or stain. It is therefore desirable for a user to protect his or her device to avoid these damages.
Apparatuses have been designed to protect handheld electronic devices against shock and other mechanical damages. U.S. Patent Application Publication, Pub. No. 2011/0309728 A1, filed by Markus Diebel on Jul. 30, 2010, discloses a case for an electronic device having a lower case portion and an upper case portion assembled together to protect an electronic device. The case effectively protects the edges and the back side of the encased electronic device. However, the front side of the device with display is open and has limited protection. U.S. Patent Application Publication, Pub. No. 2011/0266291 A1, filed by Eagle Fan on Apr. 29, 2010, teaches a protective cover for protecting an electronic device, having a cover base and a protective lid. The protective lid can be engaged with the cover base to enclose the electronic device in order to protect the front display from damage. When the protective lid is disengaged from the cover base, the front side is open and the display is exposed so that the electronic device can be conveniently used.
However, the apparatuses disclosed in U.S. Pub. No. 2011/0309728 A1 and U.S. Pub. No. 2011/0266291 A1 do not seal off the encased electronic devices. As such, water or moisture can easily get through the cases and enter into the electronic devices to cause damages, including electrical short and corrosion. Also contaminants, such as dust, dirt, grease, and stain can easily cling on to the devices, and especially the exposed display and buttons. Further, lack of protection against water and moisture can limit the utility of the encased electronic device. For example, a user is prohibited from using an electronic device held in such covers to take a picture or record a video under water. And during a rainy day one has the tendency to hide his or her device in a bag or pocket due to the concern that water can enter into the device and cause electrical damage.
Therefore, there is a need to develop a case to house a handheld electronic device with a watertight seal so that the electronic device is prevented from collecting water, moisture, and other contaminants from the environment. It is desirable that such a case also brings the benefit of preventing the encased electronic device from mechanical damages such as shock or scratch. Furthermore, it is imperative that the case facilitates regular day-to-day operations of the encased electronic device at accepted performances.